In recent years, manufacturers and suppliers of heating ventilating and air-conditioning (HVAC) equipment for automobiles have invoked initiatives aimed at increasing the efficiency of air-conditioning systems. Specifically, one area that is the subject of an initiative is preserving and improving the seals between ductwork and casing utilized in the routing of air through the air-conditioning system. An improvement in the seals, connections and ductwork of the HVAC system results in improved efficiency of the air-conditioning systems.
Foam is a traditional material used to connect ductwork pieces together and to connect ductwork to HVAC cases and air outlets. That is, foam is used as a sealing agent with the intention of creating a leak-proof seal between any duct parts, whether it be foam against foam or foam against a plastic or metal duct, foam with at least one adhesive side is used. FIG. 1 is a view of a prior art example of a duct 10 that interfaces with an HVAC case 16. The contact of the duct wall 12 and the HVAC case 16 is interposed with a piece of foam 18. The duct rim 14 is pressed into the compressible foam 18 in order to seal the interior duct passage 20 from any leaks at such interface. However, this method is not without its share of problems. For instance, typically during installation, the duct 10 and duct wall 12 are inserted into an area that cannot be seen by the installer, which causes the duct wall 12 to approach the foam 18 at an angle or in such a way as to tear the foam 18. Since the foam 18 can not be seen by the installer, the tear remains, worsens with vibration and movement of the automobile with the passage of time, and eventually air is able to leak from the interior duct passage 20 causing the overall efficiency of the HVAC system to decrease.
Another situation that causes the deterioration of the foam 18 is the mere passage of time. Historically, foam breaks down and deteriorates with the passage of time, thus resulting in looser seals between mating parts that eventually results in the leaking of air where around the foam 18. Still yet another disadvantage results when, during alignment or installation of the duct, the foam is pushed out of position, unbeknownst to the installer. When this occurs, no seal or a seal that is easily blown out of position results between the mating parts and eventually results in the leaking of air where the foam 18 resides.
Regardless of the cause, the leaking of air results in lower blowing force and lower blowing volume into the automobile cabin. This causes air-conditioning compressors to operate longer and at higher compressor displacements than if there was no leaking at the foam interfaces. This results in poor overall efficiency of an afflicted air-conditioning system. What is needed then is a method of sealing that does not suffer from the above disadvantages.
The continued development of air-conditioning systems has been directed to seals between ductwork of whatever fashion to reduce and/or eliminate misalignment, tearing of foam, or the pushing of foam out of the interface between mating surfaces.